A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3008400 can be evenly divided by 1 2 3 4 5 6 8 10 12 15 16 20 23 24 25 30 40 46 48 50 60 69 75 80 92 100 109 115 120 138 150 184 200 218 230 240 276 300 327 345 368 400 436 460 545 552 575 600 654 690 872 920 1,090 1,104 1,150 1,200 1,308 1,380 1,635 1,725 1,744 1,840 2,180 2,300 2,507 2,616 2,725 2,760 3,270 3,450 4,360 4,600 5,014 5,232 5,450 5,520 6,540 6,900 7,521 8,175 8,720 9,200 10,028 10,900 12,535 13,080 13,800 15,042 16,350 20,056 21,800 25,070 26,160 27,600 30,084 32,700 37,605 40,112 43,600 50,140 60,168 62,675 65,400 75,210 100,280 120,336 125,350 130,800 150,420 188,025 200,560 250,700 300,840 376,050 501,400 601,680 752,100 1,002,800 1,504,200 and 3,008,400, with no remainder.
Since 3,008,400 cannot be divided by just 1 and 3,008,400, it is not a prime number.